Some good stuff.
That First Body lock is too high though. That can work if you are very strong or your opponent doesn’t know to post and Hip away, but if they know what they are doing or are bigger/stronger than you it is unlikely you’ll be able to keep their hips locked to you, let alone bend them over backwards. That takedown is heavily influenced by leverage and just like with things like Armbars, a few inches off the mark can mean the difference between success and failure.
You actually want to lock your hands over their sacrum/tailbone/as far down the spine as possible and push with your shoulder/head as far up their spine as possible. If done right it will look like you are locking your hands over their butt, not the small of their back like he is doing in the video. The core of the body is generally very strong and so you need to maximize your leverage and minimize theirs if you want success with that.
The third takedown will work if you catch them with their near foot forwards, or if you can get to a side clinch where your head is behind their near arm/shoulder and can hook the leg with your outside leg or if you are much stronger than them. But locking it up like he is on even a same weight person as you is likely to have them square up to you and wind up getting pummeled to a neutral Greco Clinch (or worse). Also, his elbows are too low on that “Shield” during his entry and a big puncher would crunch your neck trying to walk in on them. You need to align your Humerus/Upper Arm bone(s) directly with the line of force so your Shield becomes a battering ram supported by your body structure behind it. With your elbows low like he is your forearms become levers and the only thing supporting your structure is your neck.
So, If you are going to do that takedown I would suggest performing the Shield correctly (which will effortlessly smash through your opponent’s attempts to punch you coming in if done right), and then once getting the body lock either doing the “back bend” takedown featured in the second video (but done correctly like I described above), or doing a duck under to get to Rear/Side Clinch where it is harder for your opponent to square up to you, strike you, and you have better control of them.
Here is a great Duck Under technique from a body lock that allows you to keep your lock/control throughout (it’s the technique that Chael is showing Okami):